1. Field of Invention
The present invention relates to an alternating current (AC) contactor with a protection function, and more particularly to an AC contactor with a mechanical short circuit self-locking function.
2. Description of Related Arts
As is known to all, in conventional controlling devices, the AC contactor is widely applied in switching and controlling power lines as an important device. Usually main contacts are used to switch the circuit and auxiliary contacts are used to execute controlling instructions. The main contacts usually include normally open contacts and the auxiliary contacts often include two pairs of normally closed and normally open contacts. A small-sized contactor is also usually used as an intermediate relay to cooperate with the main circuit.
The contacts of the AC contactors are made of silver alloy and have good conductivity and good resistance to high temperature corrosion.
In the present invention, a conventional structure able to basically accomplish functions of the AC contactor is named as an AC contactor body.
In a practical operation, when working, the AC contactor is able to accomplish opening a circuit under instructions of controlling devices; if a short circuit occurs, protecting action of a thermal relay may be untimely; thus when the contactor fails to break timely or the electrical protecting device has no self-locking protecting function against the short circuit, the AC contactor body usually would execute an instruction of the controlling device to pull in, so as to damage devices or cause fire; and also such an AC contactor body in a state of short circuit is unable to break the circuit. Based on above disadvantages, the present invention is provided after a long-time research and practice.